How do I get my money back from an accidental Amazon Prime application?

I ordered a book from Amazon about a month ago. There was an option for a free trial of Amazon Prime, I clicked it to check it out but decided against it. My understanding was that I was not signed up for it. However a $79.00 membership fee, charged to the debit card I have connected to that account tells me otherwise. I don’t want to be part of Amazon Prime and I want to get my $79 back for something I didn’t purchase. Can I do this?